[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.367301] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.681032] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 24.992807] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 25.662838] random: sshd: uninitialized urandom read (32 bytes read, 67 bits of entropy available) [ 25.844642] random: sshd: uninitialized urandom read (32 bytes read, 69 bits of entropy available) Warning: Permanently added '10.128.0.28' (ECDSA) to the list of known hosts. [ 31.521246] random: sshd: uninitialized urandom read (32 bytes read, 75 bits of entropy available) executing program [ 31.636698] BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor615/3826 [ 31.646744] caller is __this_cpu_preempt_check+0x1c/0x20 [ 31.652175] CPU: 0 PID: 3826 Comm: syz-executor615 Not tainted 4.4.148-gf057ff9 #17 [ 31.659954] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.669283] 0000000000000000 da67128bb6b772db ffff8800bb8d7570 ffffffff81e1448d [ 31.677298] 0000000000000000 ffffffff83c154c0 ffffffff83f0d440 ffff8800bba91800 [ 31.685308] 0000000000000003 ffff8800bb8d75b0 ffffffff81ebdd33 ffff8800b458c7fc [ 31.693331] Call Trace: [ 31.695896] [] dump_stack+0xc1/0x124 [ 31.701236] [] check_preemption_disabled.cold.0+0x7f/0x8b [ 31.708399] [] __this_cpu_preempt_check+0x1c/0x20 [ 31.714867] [] tcp_try_coalesce+0x22a/0x4c0 [ 31.720813] [] ? tcp_parse_options+0x970/0x970 [ 31.727016] [] tcp_queue_rcv+0x127/0x6f0 [ 31.732716] [] tcp_send_rcvq+0x3a6/0x470 [ 31.738401] [] ? tcp_rcv_established+0x1fe0/0x1fe0 [ 31.744955] [] ? do_softirq.part.16+0x20/0x60 [ 31.751074] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 31.757889] [] ? lock_sock_nested+0x90/0x120 [ 31.763922] [] ? trace_hardirqs_on+0xd/0x10 [ 31.769864] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 31.776158] [] tcp_sendmsg+0x23ec/0x2b10 [ 31.781858] [] ? sock_has_perm+0x29f/0x400 [ 31.787717] [] ? tcp_sendpage+0x17c0/0x17c0 [ 31.793667] [] ? inet_sendmsg+0x143/0x4d0 [ 31.799438] [] inet_sendmsg+0x203/0x4d0 [ 31.805038] [] ? inet_sendmsg+0x73/0x4d0 [ 31.810722] [] ? inet_recvmsg+0x4c0/0x4c0 [ 31.816495] [] sock_sendmsg+0xcc/0x110 [ 31.822008] [] ___sys_sendmsg+0x441/0x880 [ 31.827778] [] ? copy_msghdr_from_user+0x550/0x550 [ 31.834337] [] ? debug_check_no_locks_freed+0x210/0x210 [ 31.841323] [] ? tcp_v4_connect+0x1003/0x1890 [ 31.847443] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 31.853735] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 31.860485] [] ? __fget_light+0x9f/0x1f0 [ 31.866170] [] ? __fdget+0x18/0x20 [ 31.871348] [] ? sockfd_lookup_light+0xb6/0x160 [ 31.877644] [] __sys_sendmmsg+0x1d4/0x2e0 [ 31.883416] [] ? SyS_sendmsg+0x50/0x50 [ 31.888925] [] ? inet_stream_connect+0x78/0xa0 [ 31.895131] [] ? SYSC_connect+0x22a/0x300 [ 31.900905] [] ? selinux_netlbl_sock_rcv_skb+0x400/0x400 [ 31.907979] [] ? SYSC_bind+0x280/0x280 [ 31.913491] [] ? compat_tcp_setsockopt+0x44/0x70 [ 31.919868] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 31.926420] [] ? vmacache_update+0xfe/0x130 [ 31.932362] [] compat_SyS_sendmmsg+0x32/0x4